From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9593E16F82C for ; Fri, 5 Apr 2024 16:23:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712334224; cv=none; b=Bao9nW7brOy3jKVe4zF/qUN7oaGFG4myn7FPlTyLO6ljBO6aQxUyepWZDDPK0Tn7INUz89i+kj7Dd3lWVFBLtS2kZQnYKYQu4y2U+PGbtgV22B/E0YroaCy4B7CSwDdkE6oe3C3d56nsUj82HH26aZ9WI6ovmH1Fjc8tjlhsJoE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712334224; c=relaxed/simple; bh=n153wfDQ74Z0Rn0vefTD7AcUQmqSsmd933xd1EZ8jCg=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=I68AZFxjXQZhkfUmazCSQUASLjNfJI3Gf5Jb0R6+nnYHZWJH3zxuuiJX8r1Duzl9XOeqBkanqXfj3i/xre0d7rEbNEXGCyQcVD42+J5JE3vnRWXyYKnD/q1ulqjNwI/0Br2T/owSbFY2kBN4M/UFNmgWxMfusKQLZnXUDgKlNdA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=btMZJ7zQ; arc=none smtp.client-ip=209.85.210.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="btMZJ7zQ" Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-6e703e0e5deso2115082b3a.3 for ; Fri, 05 Apr 2024 09:23:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1712334222; x=1712939022; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=62HOYUcMsEfSNMd6D7XNzf+ImhMJlhPSbXFW6jY0YO4=; b=btMZJ7zQUAm9yAG7nhNfbxYN9mg+9AZbiE3DVPiVEQBbXziMjwkMiFw1+lGFtTJ3Xo I5MvLLI7lPjqNY0K3svTAcVIe4vzk1F0vWLl1aSEVJUT0fovXxqevPqmEz8M3xs2PIxj l5wE8LnnTFT/fGTY4LMph476x1CCLHAbf3cGEq7IYPda+VUHkOK/EdMWleWyG1yLpCwB t/s/tRTpZW+36uh4rU8ldeUwVNosyPsFhet0yckjG7nFdTN2eOpSy1l0B7mf2JDe0XCB 2Pvf2F3hChndt68xj3NR5AQKfih8v1w6MXxUAegjhSBLaEI02RUnOy7RDRozX4mXV5T0 kYLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712334222; x=1712939022; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=62HOYUcMsEfSNMd6D7XNzf+ImhMJlhPSbXFW6jY0YO4=; b=W1ETyGkbED6SPf1tCqP5LQ6ntImIWjOti/IRib2dPMIio3oY0ospQNtgm6sGzvZiPC E5YLTKe1UMhoO5OmdYzaZenl4OKeqGA5a9C5foZWz8lnVM3LMTNIDL7xEslS+5ZBYkSG Pd6MQTJTRz4u4JvZHoeriqgyyTLZLEdUC0i+xG0Q2etZevRorG8VWomVnkIWTq8A/iBM OqTt3rsD0u+K4o+ZGw+AfR1+/WC6jgy2sxcXBYZg0u4I01aoF6727dWZI12quRKZmwBm G3f3PXTAqjJziz7Z91/5M/k7isNHbZrhVhpwx4kGZaN1khPj22oCQlpRNlmdUe1GidxC HoKQ== X-Forwarded-Encrypted: i=1; AJvYcCVlxXL+pWeB6R+tzDUmJh/Qsz3OBOCRxkGdvc8hYSsu6ufo2whhRKVAHJYj5Gz+hYA61o1lrf6mgQq2w6yE6Z0ca6Q8 X-Gm-Message-State: AOJu0YzIa1fwzeHnt/sxqgkmyJwTZ0CUsVIPcJaqpqTxDRrsDaoGd65C MYz5Fcr++ws7MInthFH1TlhW3FaOTGaT2SRB3Ns/2NseQk81KYkc X-Google-Smtp-Source: AGHT+IFXR7XEwPfU9k7MIau6Rce/pmiil3DgtrRQfdxHcG/ju5IEJDDfO/7mjHy7Q8FjScEd4A/4Ww== X-Received: by 2002:a05:6a21:9184:b0:1a3:b155:1cd6 with SMTP id tp4-20020a056a21918400b001a3b1551cd6mr2495325pzb.8.1712334221894; Fri, 05 Apr 2024 09:23:41 -0700 (PDT) Received: from localhost ([98.97.36.54]) by smtp.gmail.com with ESMTPSA id ka32-20020a056a0093a000b006e7324d32bbsm1682783pfb.122.2024.04.05.09.23.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Apr 2024 09:23:41 -0700 (PDT) Date: Fri, 05 Apr 2024 09:23:40 -0700 From: John Fastabend To: Yonghong Song , John Fastabend , bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Jakub Sitnicki , kernel-team@fb.com, Martin KaFai Lau Message-ID: <6610258cb977b_5a9cb20838@john.notmuch> In-Reply-To: References: <20240404025305.2210999-1-yonghong.song@linux.dev> <20240404025310.2211688-1-yonghong.song@linux.dev> <66101695d69a7_5803020833@john.notmuch> Subject: Re: [PATCH bpf-next v4 1/5] bpf: Add bpf_link support for sk_msg and sk_skb progs Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Yonghong Song wrote: > > On 4/5/24 8:19 AM, John Fastabend wrote: > > Yonghong Song wrote: > >> Add bpf_link support for sk_msg and sk_skb programs. We have an > >> internal request to support bpf_link for sk_msg programs so user > >> space can have a uniform handling with bpf_link based libbpf > >> APIs. Using bpf_link based libbpf API also has a benefit which > >> makes system robust by decoupling prog life cycle and > >> attachment life cycle. > >> > >> Signed-off-by: Yonghong Song > >> --- > >> include/linux/bpf.h | 6 + > >> include/linux/skmsg.h | 4 + > >> include/uapi/linux/bpf.h | 5 + > >> kernel/bpf/syscall.c | 4 + > >> net/core/sock_map.c | 268 ++++++++++++++++++++++++++++++++- > >> tools/include/uapi/linux/bpf.h | 5 + > >> 6 files changed, 284 insertions(+), 8 deletions(-) > >> > > LGTM one question below. > > > >> +/* Handle the following two cases: > >> + * case 1: link != NULL, prog != NULL, old != NULL > >> + * case 2: link != NULL, prog != NULL, old == NULL > >> + */ > >> +static int sock_map_link_update_prog(struct bpf_link *link, > >> + struct bpf_prog *prog, > >> + struct bpf_prog *old) > >> +{ > >> + const struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link); > >> + struct bpf_prog **pprog; > >> + struct bpf_link **plink; > >> + int ret = 0; > >> + > >> + mutex_lock(&sockmap_mutex); > >> + > >> + /* If old prog is not NULL, ensure old prog is the same as link->prog. */ > >> + if (old && link->prog != old) { > >> + ret = -EINVAL; > >> + goto out; > >> + } > >> + /* Ensure link->prog has the same type/attach_type as the new prog. */ > >> + if (link->prog->type != prog->type || > >> + link->prog->expected_attach_type != prog->expected_attach_type) { > >> + ret = -EINVAL; > >> + goto out; > >> + } > >> + > >> + ret = sock_map_prog_lookup(sockmap_link->map, &pprog, > >> + sockmap_link->attach_type); > >> + if (ret) > >> + goto out; > >> + > >> + /* Ensure the same link between the one in map and the passed-in. */ > >> + ret = sock_map_link_lookup(sockmap_link->map, &plink, link, false, > >> + sockmap_link->attach_type); > >> + if (ret) > >> + goto out; > >> + > >> + if (old) { > >> + ret = psock_replace_prog(pprog, prog, old); > >> + goto out; > >> + } > >> + > >> + psock_set_prog(pprog, prog); > >> + > >> +out: > >> + if (!ret) { > >> + bpf_prog_inc(prog); > >> + old = xchg(&link->prog, prog); > >> + bpf_prog_put(old); > > Need to check old? I don't think we can clal bpf_prog_put on null? > > > > if (old) > > bpf_prog_put(old) > > The 'old' here represents the *old* link->prog program and > link->prog should not be NULL at this point. Ah ok. Maybe instead of using the input old var make it explicit? if (!ret) { struct bpf_prog *old_link; bpf_prog_inc(prog); old_link = xchg(&link->prog, prog); bpf_prog_put(old) } Is a bit more obious to me at least. Up to you I have a slight preference for the explicit more verbose above. Otherwise for the series. Reviewed-by: John Fastabend